*{
    margin: 0;
    padding: 0;
}
.container{
    width: 750px;
    height: 350px;
    position: relative;
}
.list{
    list-style-type: none;
    width: 750px;
    height: 350px;
}
.item{
    width: 100%;
    height: 100%;
    position: absolute;
}
.item:nth-child(1){
    background-image: url(../images/1.jpg);
    background-repeat: no-repeat;
}
.item:nth-child(2){
    background-image: url(../images/2.jpg);
    background-repeat: no-repeat;
}
.item:nth-child(3){
    background-image: url(../images/3.jpg);
    background-repeat: no-repeat;
}
.item:nth-child(4){
    background-image: url(../images/4.jpg);
    background-repeat: no-repeat;
}
.item:nth-child(5){
    background-image: url(../images/5.jpg);
    background-repeat: no-repeat;
}
.btn{
    width: 30px;
    height: 60px;
    position: absolute;
    top: 145px;
    background-color: rgba(0, 0, 0, 0.7);
    border: none;
    color: #fff;
    outline: none;
    z-index: 11;
}
#left{
    left: 20px;
}
#right{
    right: 20px;
}
.item.active{
    z-index: 10;
}